Green’s Dictionary of Slang

(US) a general excl., usu. implying pleasure rather than fury.

1920		H. Wiley Wildcat 80: ‘Hot damn!’ he exclaimed.
1935		(con. late 1920s) L. Hughes Little Ham III i : Well, hot-damn!
1947		W.D. Overholser Buckaroo’s Code (1948) 15: Hod [sic] dang it, Cotton, why didn’t we eat at Charlies?
1949		(con. 1943–5) A. Murphy To Hell and Back (1950) 119: ‘This woman’s a snowball [...] She’s fulla dope.’ ‘Hod damn [...] who’da thought it?’.
a.1954		‘Ball of the Freaks’ in D. Wepman et al. Life (1976) 110: ‘Hot damn!’ cried the faggots as they dig the maggots / Crawling out of that bitch’s hips.
1965		H. Rhodes Chosen Few (1966) 16: ‘Hot dammit!’ he cursed, rubbing his knee.
1968		N. Heard Howard Street 68: ‘Hot damn!’ Brother shouted joyously.
1971		B. Moyers Listening to America 26: ‘Hot dang,’ someone says.
1978		A. Maupin Tales of the City (1984) 19: Hot damn. This place is Pickup City tonight.
1988		P. Califia Macho Sluts 44: Did that really happen? Hot damn! And I think I’m wicked and perverse.
1996		J. Cameron It Was An Accident 189: Hot damn! Now we got to think up some other scheme.
2000		C. Cook Robbers (2001) 23: Hot damn [...] Look out Houston, here we come.